Firefox will not start in my Windows 10. All I get is the little windows progress circle for about 5 seconds, then nothing. no error messages displayed.--I updated Firefox the morning before the issue began.--I have uninstalled, then downloaded and installed Firefox.--When trying to access the Firefox Profile Manager using "C:\Program Files\Mozilla Firefox\firefox.exe" -P in the start box, nothing happens. So I tried to create a new Profile manually.

--Am I correct when I created a new profile manually by 1. First creating a new folder in the Profiles folder, named the file Profiles\filename.default2. In the Profiles configuration file I set the path to the new Profile as Path=Profiles/filename.default3. Then I copied the suggested minimum files specified at http://kb.mozillazine.org/Transferring_ ... _-_Firefox but Firefox wouldn't start. 4. I systematically renamed each file to try to isolate a potential corrupted file, and tried to start Firefox but no file appeared to be the cause of the crash as Firefox still wouldn't start.

Any suggestions? I have used Firefox for years and there is a mountain of information being held there. I don't want to have to change to another browser.

"Manually" creating a new profile is a rather unusual step and, of course, uninstalling and reinstalling the application itself has absolutely no impact on your Profile.Have you confirmed that Firefox is not running in the Windows Task Manager but not displaying the user interface?Despite running a 64bit operating system, if you have been running a 32bit version of Firefox the correct entry in the start box would be "C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -P

Thanks for the quick reply. Yes, I confirmed that Firefox isn't running in the Processes in the Task Manager. And I get no results when I enter in the start box "C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -P

In case it rings a bell with you, Firefox was OK until I was troubleshooting a Wordpress install on a development site on a Godaddy server (Managed Wordpress-- never again.) I was slashing rapidly through disabling 15 or so plugins to isolate which one may be causing a functionality issue I was having. At each disable I then went to a separate browser (Chrome) and tested a login/register page.

You may remember that on Managed WP it's best to flush cache frequently or you won't see the correct page versions. So I did that frequently.

After that I started noticing issues. Then Firefox stopped working. And my site is not working properly here and there.

As a temporary workaround until you make other progress you should be able to get Firefox Portable to run. And after you test it you can attempt to copy your places.sqlite into the Portable's data directory to get your bookmarks available. https://portableapps.com/apps/internet/firefox_portable

I have been having this problem as well for the past 3 days. It started on the 11th. So far, I've tried the following methods, but with no such luck:

--Restarting my computer--Disabled all (but one at a time) of my extensions--Cleared my cache and cookies

Only other things I haven't tried are starting up in safe mode (which I don't know how to do from the start,) and resetting Firefox (which I'm hesitant to do because I don't want to lose all my bookmarks and passwords. Additionally, my problem seems to be different from the one previous stated... Whenever I try to reopen my browser, it "opens" according to the task manager, but it doesn't actually open. Here is a screencap of what I mean.https://i.imgur.com/Wuqluwf.png

The only instances I am able to get on is to click on a permalink that was posted on another outlet, like Skype for example, by clicking the same link over and over until something appears, in which case, I wind up having to "end proces" all the other useless firefox.exe programs excluding the correct one as seen here:https://i.imgur.com/4NovaVy.png

Is this that "Startup crash with RelevantKnowledge adware installed. Firefox Support has helpful instructions to remove it" issue that ver. 56.0.1 has unresolved yet?

Last edited by BigJohnnyCool on October 14th, 2017, 10:13 am, edited 1 time in total.

After closing (Ending) all instances of Firefox in the Task Manager's Processes list, you can try launching Firefox to Safe Mode by holding down the Shift key and clicking on the desktop shortcut for Firefox.

Allande, I installed Firefox Portable and it won't run either. I get their little opening screen and then it goes away after 3--4 seconds. It doesn't appear in the Task Manager.

I installed Firefox Portable on an external hard drive and then on the desktop and neither works. Same results-- stops after 3--4 seconds.

Question: I'm getting desperate, so I'm thinking about a Windows system restore to an automatic restore date of 10/9, before all this started. Before a FF update and a couple of other program updates. Will this restore my profile to the 10/9 date also?

DanRaisch wrote:After closing (Ending) all instances of Firefox in the Task Manager's Processes list, you can try launching Firefox to Safe Mode by holding down the Shift key and clicking on the desktop shortcut for Firefox.

That doesn't work for me. I've tried it and I'm never given the prompt to startup in Safe Mode. If I'm already opening it up in Safe Mode, then it still isn't activating for me.